A TSP (Touch Screen Panel) in Cell technology is to manufacture a TSP sensor and a driving circuit thereof on an array substrate by means of an array process. Through the integration of the TSP sensor into a liquid crystal cell of a LCD (Liquid Crystal Display) panel, it is able to achieve a light and thin product, to provide diverse functions, and to effectively improve the reliability of the touch screen panel.
FIGS. 1(a) and 1(b) show a basic light-induced TSP in Cell circuit in the prior art. In FIG. 1(a), a sensor senses the light by means of a photodiode D1 and generates an electric leakage so as to detect a touch signal. In FIG. 1(b), the sensor senses the light by means of an induction capacitor C2, and detects a touch signal depending on the coupling of the induction capacitor and a variation of the capacitance. A TFT (Thin-Film Transistor) T1, as an amplifying transistor, is configured to amplify a voltage change cross D1 after detecting the touch signal, and enhance the output driving capability of the TSP in Cell circuit, so as to enable a readout circuit of the external TSP to read out a detection result correctly.
As compared with a traditional liquid crystal panel, an AMOLED (Active Matrix Organic Light Emitting Diode) has advantages of a rapider response speed, higher contrast and a wider angle of view. Pixels of the AMOLED are driven by a relevant driving circuit on the array substrate so as to emit light and display. FIG. 2 shows an example of an AMOLED pixel unit circuit.
If the TSP in Cell circuit as shown in FIG. 1(a) or FIG. 1(b) is simply integrated into the AMOLED pixel unit circuit as shown in FIG. 2, three TFTs and one capacitor, apart from the existing five TFTs and two capacitors, are required to be added. In addition, three control signals, apart from the existing three control signals and two power sources, are also required to be added to control signal lines. However, there is no enough room for the pixels of AMOLED to accommodate these additional TFTs and signal lines. As a result, it is unable to integrate the TSP in Cell circuit into the AMOLED pixel unit circuit in the prior art.